Question

which digestive secretion is the most acidic?
a. bile
b. saliva
c. gastric juice
d. pancreatic juice

Explanation:

• Bile: It has a pH of about 7.6 - 8.6 (alkaline). It helps in the emulsification of fats.
• Saliva: The pH of saliva is around 6.2 - 7.6 (slightly acidic to neutral). It contains enzymes like amylase for carbohydrate digestion.
• Gastric juice: It has a pH of 1.5 - 3.5. It contains hydrochloric acid ($HCl$) which makes it highly acidic. The low pH helps in activating pepsinogen to pepsin (for protein digestion) and also has a bactericidal action.
• Pancreatic juice: It has a pH of 7.5 - 8.8 (alkaline). It contains enzymes like trypsin, amylase, lipase etc. and bicarbonate ions which neutralize the acidic chyme coming from the stomach.

Answer:

C. Gastric juice